Addex Therapeutics completes enrollment in ADX71149 epilepsy phase 2 study part 1

Addex Therapeutics, a clinical-stage pharmaceutical company, announced the completion of Part 1 of the phase 2 clinical study of ADX71149 (JNJ-40411813) for the treatment of epilepsy. ADX71149 is a positive allosteric modulator of the metabotropic glutamate type 2 (mGlu2) receptor (PAM). Janssen Pharmaceuticals, Inc., a subsidiary of Johnson & Johnson's Janssen Pharmaceutical Companies, is conducting the trial. An independent interim review committee (IRC) will now evaluate data from Part 1 to ensure the study remains blind. Janssen will assess the program's next steps based on the results of this review and the IRC's recommendations.

“The phase 2 study evaluating ADX71149 in epilepsy continues to make progress and we are pleased our collaboration partner has completed enrollment into Part 1 of the study,” said Tim Dyer, CEO of Addex. “We look forward to the outcome of the IRC review and the next steps for the program which are expected around the end of Q1 2023.” The multi-center phase 2 study is designed to assess the efficacy, safety, tolerability and pharmacokinetics of adjunctive ADX71149 administration in epilepsy patients with focal onset seizures with suboptimal response to levetiracetam. The primary objective of the study is to evaluate the efficacy of ADX71149 in combination with levetiracetam using a time to seizure event endpoint. Part 1 of the study evaluated the acute efficacy of ADX71149 over 4 weeks. Patients who do not reach or exceed their monthly baseline seizure count in Part 1 will have the opportunity to continue double-blind treatment during Part 2, deemed the maintenance efficacy phase (8 weeks). Patients who complete Part 1 are eligible to enter the open-label extension period. Glutamate is the primary excitatory neurotransmitter in the brain and plays a key role in the initiation and spread of seizures. When activated, the mGlu2 receptor is believed to decrease the release of glutamate and consequently help to maintain neurotransmitter balance.

In the presence of agonist-induced activation, positive allosteric modulation of mGlu2 receptors could result in the normalization of the excessive glutamate release seen during a seizure. There is still an urgent need for more effective treatments for epilepsy, with improved tolerability and safety. ADX71149 was described in the Eilat 15 conference summary review as a promising novel approach currently in development (Bialer et al., 2020. Epilepsia). Proof of concept data with ADX71149 and other mGlu2 PAMs in animal models of epilepsy have been published in peer-reviewed journals (Metcalf et al., 2017 and 2018. Epilepsia). Under the research collaboration and license agreement, Addex granted Janssen Pharmaceuticals, Inc. an exclusive worldwide license to develop and commercialize mGlu2 PAM compounds.

Addex is eligible for up to a total of €109 million in success-based development and regulatory milestone payments. In addition, Addex is eligible for low double-digit royalties on net sales of compounds developed under the agreement. Addex Therapeutics is a clinical-stage pharmaceutical company focused on the development and commercialization of an emerging class of novel orally available, small molecule drugs known as allosteric modulators for neurological disorders.